R1272S032A033-0500EV: 3.3V @ 10A, 4 ~ 34V in


The R1272S is a step-down DC/DC controller which can generate an output voltage of 0.7 to 5.3V by driving external high/low-side NMOSs. By the adoption of a unique current mode PWM architecture without an external current sense resistor, the R1272S can make up a stable DC/DC converter with high efficiency even with externally added low Ron MOSFETs and low DCR inductor. And, by the frequency characteristics optimization with using external phase compensation capacitor, the R1272S can achieve a high-speed response to variations in input voltage and load current.

The oscillation frequency is adjustable over a range of 250 kHz to 1 MHz (1) by external resistors and can also be synchronized to an external clock. Output Voltage Control Methods have three operating modes: Forced PWM mode, PLL_PWM mode, and PWM/VFM Auto-switching mode. These modes are selectable according to conditions of the MODE pin. Especially, the PWM/VFM Autoswitching mode can improve efficiency under light load conditions.

In automotive application, R1272S can minimize the output voltage drop caused by an input voltage drop at cranking, by reducing the operating frequency (the lowest possible limit is 1/4 of the frequency) so that the off-duty time is reduced. Protection functions include a current limit function, an UVLO (Under Voltage Lock Out) function, an OVP (Over Voltage Protection) function, a soft-start function, a low-inductor current shutdown function, and so on. Also, a power good function provides the status of the output with a power good (PGOOD) pin.


Manufacturer RICOH Electronic Devices Co., LTD.
Category AC/DC and DC/DC Conversion
Sub-Category DC/DC SMPS - Single Output
Eval Board Part Number 2129-R1272S032A033-0500EV-ND
Eval Board Supplier RICOH Electronic Devices Co., LTD.
Eval Board Normally In Stock
Topology Step Down
Outputs and Type 1 Non-Isolated
Voltage Out: Factory Set 3.3 V
Current Out 10 A
Voltage In 4 ~ 34 V
Efficiency @ Conditions >94%, 8V in, 3.3V @ 10mA ~ 2A (PWM-VFM)
>92%, 8V in, 3.3V @ 1 ~ 10A (PWM)
>92%, 12V in, 3.3V @ 10mA ~ 2.5A (PWM-VFM)
>92%, 12 Vin, 3.3V @ 2 ~ 10A (PWM)
>91%, 16 Vin, 3.3V @ 10mA ~ 3A (PWM-VFM)
>91%, 16 Vin, 3.3V @ 1 ~ 10A (PWM)
Voltage Out Range 0.7 ~ 5.3 V
Features Current Limit (Adj. or Fixed)
Light Load Mode
Over Voltage Protection
Power Good Output
Shutdown, Enable, Standby
Soft Start
Under Voltage Protection, Brown-Out
Switching Frequency 500 kHz
Standby Current [Typical] 3 µA
Quiescent Current [Typical] 1.9 mA
Component Count + Extras 21 + 5
Internal Switch Yes
Design Author RICOH Electronic Devices Co., LTD.
Application / Target Market Cell Phones
Digital Cameras
DVD/Blu-ray Players
Printer, Plotter
Set-Top Boxes
Standby Current [Maximum] 20 µA
Quiescent Current [Maximum] 1.6 mA
Main I.C. Base Part R1272S
Date Created By Author 2020-06
Date Added To Library 2020-09

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